International Space Station (iss)
quest (joint airlock)
The Quest Airlock connects to the starboard port of Node 1. (Unity). The External Stowage Platform 2. is attached to the forward facing side of Quest.
The Quest Airlock connects to the starboard port of Node 1. (Unity). The External Stowage Platform 2. is attached to the forward facing side of Quest.
The Joint Airlock "Quest" is a pressurized module which provides station-based Extra Vehicular Activity (EVA), or space walking. Crew wearing either U.S. Extravehicular Mobility Unit (EMU) space suits or Russian Orlan space suits can use the airlock.
Before Quest, EVA's in US suits could only be made via a space shuttle airlock when it was docked to the Station. Also EVA's using Russian suits could only be made from the FGB (Zarya) docking compartment. This required isolating sections of the station and resulted in major loss of environmental consumables such as air.
The arrival of the Russian Docking Compartment 1 [DC-1] (Pirs) on September 16, 2001 provided another airlock for space walks using Russian Orlan space suits.
Material: aluminium
Length: 5.5 meters (18 ft)
Diameter: 4 meters (13 ft)
Mass: 6,064 kilograms (13,369 lb)
Volume: 34 cubic meters (1,200 cu ft)
Cost: $164 million, including tanks
Quest consists of two cylindrical chambers attached end-to-end by a connecting bulkhead and hatch. The larger section, called the 'Equipment Lock', is attached to Node 1. (Unity) and acts as a staging area for crew members preparing to conduct an EVA. This section also has a storage area inside for US space suits.
The smaller section, called the 'Crew Lock', contains the EVA departure / entry hatch for crew to exit into space and return.
Quest was derived from the U.S. Space Shuttle airlock and significantly modified to waste less atmospheric gas when used. It also supports four high-pressure gas tanks which provides for atmospheric replenishment for the gas lost after a hatch opening during a space walk.
Quest was necessary because American suits will not fit through a Russian airlock hatch and have different components, fittings, and connections. The airlock is designed to contain equipment that can work with both types of space suits.
The airlock and tank systems were built by the Boeing Company and tested at NASA's Marshall Space Flight Center in Huntsville, Alabama.
Quest also supports the High Pressure Gas Assembly which consists of four gas tanks (two oxygen and two nitrogen) attached to the outside of the larger section (Equipment Lock). These support EVA operations and augment the Service Module (Zvezda) gas re-supply system.
The tanks were transported to the station attached to a Space Lab Double Pallet in the U.S. Space Shuttle's cargo bay on mission STS-104 (Flight 7A). The tanks were then attached externally to the airlock during two EVA's.
These tanks provide a replenishable source of gas to the Atmosphere Control and Supply System and 900 psi (6.2 MPa) oxygen for re-charging the space suits (EMUs). The tanks can be recharged from a shuttle docked to the Station's Pressurized Mating Adapter 2 or 3 [PMA-2 or 3] using the Oxygen Recharge Compressor Assembly [ORCA].
As the Space Shuttle fleet is now retired this task has been replaced by the Nitrogen Oxygen Recharge System (NORS) and spacecraft from the Commercial Orbital Transportation Services (COTS) program.
Quest was permanently installed on the starboard berthing port of the Node 1. (Unity) on July 14, 2001 during U.S. Space Shuttle mission STS-104 [Flight 7A].
It then became the primary path for station EVA using U.S. space suits.
Quest provides an environment where astronauts can 'camp out' before a space walk in a reduced-nitrogen atmosphere. This purges nitrogen from their bloodstream to avoid decompression sickness in the low-pressure (5 psi, 34 kPa) pure-oxygen atmosphere of the spacesuit.
The previous method of preparing for space walks involved breathing pure oxygen for several hours prior to an EVA to purge the body of nitrogen.
The 'camping out' procedure was first tested in April 2006 when two station crew members spent the night in the Airlock chamber with pressure reduced from the normal 14.7 to 10.2 psi (101 to 70 kPa).
U.S. space walk activities have since employed the 'camp-out' pre-breathing technique.
